There has known of a recording medium drive device for recording an information signal or reading the information or both of recording and reading information with respect to a recording medium in a disk cartridge rotatably accommodating a disk-shaped recording medium such as a magneto-optic disk or a magnetic disk.
Such a recording medium drive device is provided with a holder for holding the disk cartridge. When the disk cartridge is inserted into the holder, a shutter slidably supported on the case of the disk cartridge is opened. Information is recording on or information is read from the rotating recording medium via the opening.
In a recording medium drive device of a type where a disk cartridge is inserted into a holder, the disk cartridge must be inserted into the holder in the correct direction. For this reason, a unit for preventing erroneous insertion of the disk into the holder is provided.
As such a unit for preventing erroneous insertion in a recording medium drive device, for example Japanese Unexamined Patent Publication (Kokai) No. 8-96463 discloses the technique of providing an erroneous insertion prevention projection at one side of the holder opposite to the side where the shutter opening/closing mechanism is provided. In this recording medium drive device, for example, when the disk cartridge is inserted into the holder in the correct direction, the projection is inserted into an erroneous insertion prevention groove formed in one side of the case of the disk cartridge, so the disk cartridge can be inserted deep into the holder. If the disk cartridge is inserted into the holder in the erroneous direction, however, the side of the case where the groove is not formed is inserted facing the projection, therefore the projection strikes the case. This stops the insertion of the disk cartridge into the holder and thereby prevents erroneous insertion of the disk cartridge into the holder.